Current methods for guiding cancer biopsies rely almost exclusively on X-ray, ultrasonic, or magnetic-resonance derived images. While these methods are far more accurate than the age-old technique of palpation, all three still essentially characterize suspected lesions based only on tissue density. Contractor will integrate chemically-sensitive optrodes into the biopsy needle, leaving the main channel clear for unimpeded trocar passage and aspiration, while providing the physician with real-time information on tissue viability and metabolic state. This will allow precision-guided collection of samples suitable for molecular biomarker profiling. In this Phase I project, contractor will fabricate a 3-sensor demonstration system that can easily be adapted for GMP manufacture, show that it accurately records target chemical concentrations in laboratory tests, and prove the viability of its principle of operation through animal studies. The Biopsy Optical Sensor for In Situ Tissue Analysis (BOSISTA) will integrate hair-thin optical fiber sensors into conventional biopsy needles to bring biopsy practice into the 21st century. By monitoring chemical changes in and around suspected tumors instantaneously during the procedure, doctors will be able to perform biopsies more quickly, and produce results that are much more useful for fighting cancer.